Year	Number
2004-01-01	21
2005-01-01	24
2006-01-01	26
2007-01-01	28
2008-01-01	29
2009-01-01	30
2010-01-01	29
2011-01-01	15
2012-01-01	14
2013-01-01	14
2014-01-01	12
2015-01-01	11
2016-01-01	10
2017-01-01	9